1. Field of the Invention
The present invention relates to a tufting machine for producing tufted fabrics, such as tufted carpets and mattresses, and more particularly to a tufting machine which can control the movements of individual needles.
2. Description of the Prior Art
To produce tufted fabrics docorated with a variety of patterns the common practice is that colored piles are inserted into a backing fabric by needles, which are supplied with threads of different colors one after another, and individually selected for stitching the fabric.
To produce a variety of nap on the backing fabric with planted piles many types of needles have been developed. A lot of effort has been focused on the "individually controlled needles (commonly referred to their abridged ICN)", among which is an invention disclosed in Japanese Patent Publication (unexamined) No. 59-179863. This prior art machine comprises a needle bar, a plurality of needles retractibly mounted on the bar, and steel cords connecting the needles and a common pneumatic cylinder so that the selectively needles can be operated by the pneumatic force whereas the others remain out of operation. The piles are inserted into the backing fabric uner individual control so as to produce the required pattern.
This prior art machine requires the pneumatic cylinder to operate each stitching cycle, and the following disadvantages result:
(1) The pneumatic cylinder must have a large capacity;
(2) The speed at which the needles are operated is limited, thereby resulting in the inefficient tufting performance; and
(3) Because the needle bar is necessarily provided with sliders or pistons operated by the cords there must be a sufficient space around each needle so as to accommodate the slider or piston. To secure the space needles are provided at relatively large intervals, thereby leading to a coarse tufting.
To overcome the difficulties pointed out above there is another proposal disclosed in Japanese Patent Publication (unexamined) No. 60-39466. According to this invention the needle bar is additionally provided with a means for enabling the same to move up and down each stitching cycle, so that the tufting is carried out by the selected needles operated in association with the needle bar. As a result the difficulties (1) and (2) mentioned above have been overcome. However the difficulty (3) remains unsolved, and a new inherent difficulty has arisen in producing high and low nap in each stitching line, thereby leading to the lack of colorful patterns.